Technical Field
This disclosure relates to a sound absorber, a sheet feeder incorporating the sound absorber, an image reading device incorporating the sheet feeder, an image forming apparatus incorporating the sound absorber, and an electronic device incorporating the sound absorber.
Related Art
Electrophotographic image forming apparatuses include a sound absorber that restrains leakage of a drive sound to an outside of the sound absorber.
A known image froming apparatus includes a sound absorber that has a structure of Helmholtz resonator by including a cavity and a communicating portion that allows communication between the cavity and an outside of the sound absorber, so that the sound absorber absorbs a sound generated at the time of image formation by the image forming apparatus.
Such a sound absorber having a configuration of Helmholtz resonator has different sound absorption efficiencies depending on the communication direction from the cavity to the outside of the sound absorber and the position of a sound source with respect to the sound absorber. When the sound absorber is installed in the image forming apparatus, the communication direction of a communication portion is not constantly a direction having a high sound absorption efficiency. Therefore, when the direction has a low sound absorption efficiency, an abnormal sound can occur during image formation and may be transmitted to the outside the image forming apparatus.